Expanded Explanation
Docker lets developers bundle code, runtime, libraries, and configuration into a single container image that runs consistently across laptops, servers, and clouds. It has become a standard building block of modern software delivery pipelines.
Simple explanation
Docker puts your app into a sealed box with everything it needs, so it runs the same on any computer.
Real-world Applications
Microservices deployment
Reproducible development environments
CI/CD pipelines
Local testing of production stacks
Advantages
- Portable across environments
- Faster than virtual machines
- Simplifies dependency management
Limitations
- Not a full security boundary by itself
- Requires orchestration at scale (see Kubernetes)